New archive file format (was: [omgps] collect feature requests)

Laszlo KREKACS laszlo.krekacs.list at
Thu Jul 2 08:58:55 CEST 2009

On Thu, Jul 2, 2009 at 7:22 AM, mqy<meng.qingyou at> wrote:
> XML is used as a database, elements can be easily added, modified, removed.
> xor tends to be overkilled as of map tile usage -- we don't need iterating,
> delete, and that much meta information. With my suggested design, we can
> even add newly downloaded tiles:
> insert record into meta database, and append tile content into "heap" file.

If I understand right the OSM tiles, they have the following directory

All the information is obtained from this info (position, zoom level),
am I right?
XX: zoom level
YYY: position x? (or I dont know how to call it;)
ZZZ: position y?

So I think we should only pack the files into the KISS archive file.
For more in depth explanation see the end of this mail.

So something like this:

Im willing to implement a simple kiss/unkiss program (just like tar/untar),
for easy archiving.
I will use python with no non-standard modules.

Best regards,

Some statistical data:

Number of all tiles
# cd ~/Maps/OSM; find . -name *.png |wc -l

Subdirs in zoom level dirs (YYY), and total number of files.
for i in *; do echo -n $i; echo -n " "; cd $i; ls -1|wc -l; cd ..; done
for f in *; do cd $f; for i in *; do cd $i; for k in *; do echo
"$i/$k" >> ~/Maps/OSM/$f.txt; done; cd ..; done; cd ..; done
cd ~/Maps/OSM
for i in *.txt; do echo -n "$i "; cat $i|wc -l ; done

2:   4 dirs,     16 files
3:   8 dirs,     64 files
4:   11 dirs,    77 files
5:   17 dirs,    83 files
6:   22 dirs,   265 files
7:   22 dirs,   217 files
8:   17 dirs,    75 files
9:   26 dirs,   152 files
10:  39 dirs,   426 files
11:  71 dirs,  1484 files
12: 100 dirs,  1046 files
13:  78 dirs,  2902 files
14: 193 dirs, 23400 files
15:  86 dirs,  1941 files
16: 119 dirs,  4033 files
17: 277 dirs, 27637 files

Count the files in the subdirs(ZZZ):
for i in *; do echo -n $i; echo -n "f "; cd $i; for j in *; do cd $j;
echo -n "$i # $j @"; ls -1|wc -l; cd ..; done; cd ..; done

The number of files is in general 20-30, and the maximum was 180.

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